Sealing device for centrifugal pumps



Oct. 15, 1935. A. 1 MCHUGH 2,017,544

SELING.' DEVICE FOR CENTRFFGAL PUMPS Filed Aug. '7, 1955 2 snets-sheet 1 10 V J 'A 31+ 5 25 L 1 W Xin, A ///////////4 INVENToR. 8 nfz yL-JIIcIlzff/z H15 ATTORNEY Oct. 15, 1935. A. l.. MGHUGH '2,017,544

` v SEALING DEVICE. FOR CENTRIFUGAL PUMPS y Filed Aug. 7. 1935 2 Sheets-Sheet 2 1N VEN TOR.

HIS A TTORNEY Patented @et l5, i935 SEALING DEVICE FOR CENTRIFUGL Films .anthony L. McHugh, Easton, Pa., assignor to Ingersoll-Rand Company, `Hersey City, N. S., a corporation of New .iersey Application August 7, 1935, Serial No. 35,081

3 Claims.

This invention relates to improvements incentrifugal pumps and more particularly to a sealing device for vertically split centrifugal pumps whereby a flexible seal is provided between the 5 shell or casing of the pump and the stator parts thereof.

Vertically split pumps are commonly constructed with a` cylindrical casing or shell or barrel adapted to have its ends closed by heads in which an impeller shaft may be journaled. The rotor parts are assembled upon the shaft in any conventional manner and the stator or diaphragm is made up of a series of annular segments adapted to be held tightly against each other to form diffusers or stage connections between the outlet of one impeller and the inlet of another. Such pumps are often used for pumping fluids of relatively high or low temperatures such as hot oil, boiler feed water or brine, the temperature effect of which is more pronounced upon the pump mechanism than upon the barrel or casing so that there will be a greater expansion or contraction (as the case may be) of the former than the latter. This differential expansion is likely to break any non-resilient seal and open leakage points between the barrel or casing and its head or closure.

It is an object of this invention to provide a.A flexible seal of simple and inexpensive construction which may be readily applied to a pump of the type described and which will furnish a pressure tight and effective seal under all conditions of temperature and pressure.

Other objects are either apparent or will be set forth hereinafter.

In the accompanying drawings, Fig. l represents a longitudinal view partly in section of a centrifugal pump to which the invention has been applied.

Fig. 2 is a view taken upon the lines 2--2 of Fig. 1 and looking in the direction of the arrows in which the invention is further illustrated, and Fig. 3 is an enlarged sectional View illustrating the detail of one part of Fig. 1, and

Fig. 4 is an enlarged sectional view showing a.

modification of the invention.

Referring to the drawings in which similar reference characters denote similar parts, a casing or barrel IIJ is closed at each end by heads I2.

A suitable inlet I4 is provided in one head and a similar outlet I 6 is provided in the other. The heads may be conveniently fixed to the barrel by bolts I8. Journaled in suitable bearings in the heads (which bearings are not more particularly described because they are not an essential feature of the invention) is a shaft 20 upon which are (Cl. 10S-lll) mounted, by suitable means such as keys and keym Ways 40, a, pair of impellers including a low pres sure impeller 24 and a high pressure impeller 23. The diffuser passages between the rst stage impeller 24 and the second stage impeller 26 and tl between the second stage impeller 26 and the outlet I6 are formed in diaphragm segments 28, 30 and 32, these segments being annular members which are assembled within the barrel I0 to form the diaphragm or stator of the centrifugal pump. 10

The elements 30 and 32 are held together by means of a bolt 36 having a hollow head in which a spring 38 may be inserted. Clamped between the elements 30 and 32 is a exible metallic member in the form of an annular gasket 34 the inner l5 edge of which is held firmly between vthe members 30 and 32. The outer edge of the gasket 34 is clamped between the barrel I0 and its head I2 by means of the bolts I8. The central portion of the gasket 34 is unsupported, being freed from con- 20 tact with the segments30 and 32 because of a. bevel provided at the periphery of the segments 30 and 32. It will be seen from this construction that upon elongation of the stator elements under the influence of heat the flexible gasket 34 may 25 bend slightly to the left and upon contraction or shortening owing to the effects of low temperature the gasket 34 may bend to the right, but at all times a. complete seal is made between the diaphragm segments and the barrel and head. 80

In the modification illustrated by Fig. 4 the seal is shown at the inlet end of the pump and differs in form, though not in principle, from the type just described. 'Ihe impeller 24 discharges into a diffuser passage 25 formed in a diaphragm seg- 35 ment 28. The barrel or shell I0 is provided with a shoulder 50 against which a Washer 52 may be fitted. In the head I2 is an annular recess 54 in which an annular flange 56 of a metallic gasket 58 may be pressed. 40

The gasket 58 in this instance is in the form of an annular plate having a heavy flange 56 at its inner edge and a lighter flange or shoulder 60 near its periphery. That part of the plate outside of the shoulder 60 is pinched between the dia- 45 phragm segment 28 and the shoulder 50 on the barrel I0, the flange 60 overlapping the joint between the washer 52 and the shoulder 50. Intermediate the flanges 60 and 56 the plate 58 is l dished as clearly appears in the drawings. The 50 tendency of the deflected or dished portion to hatten out exerts pressure against the flanges 56 and 60, and the latter is urged firmly against the washer 52 and the shoulder 5U of the barrel I0. The deflection of the intermediate part of the B5 plate 58 provides a resilient seal which can accommodate itself to relative movement between the cylinder and the diaphragm ofthe pump.

In order to provide space for the shoulder 60 and the deection of the dished portion of the plate 58 a depression 62 is formed in the head I2.

In the diaphragm segment 28 a series of bores 64 act as seats for springs 6d which exert pressure against an annular ring 68. This ring bears upon the inner part of the gasket 58 and urges the inner shoulder 56 into the recess 54.

As an additional seal, although adding nothing to the flexibility of the assembly,the inner edge of the gasket 58 may be welded to the head l2 as shown at 1D.

By either of these simple and inexpensive devices I have provided a seal which is eicient in making a pressure tight joint at the head of a centrifugal pump, but at the same time providing suicient flexibility to take care of any reasonable expansion or contraction due to high or low temperatures.

Having thus disclosed my invention I do not desire to be limited to the exact disclosure, but

claim:

1. In a centrifugal pump of the type described, a cylinder, a pair of heads therefor, a plurality of segments forming a diaphragm assembled in the cylinder, an annular iiexible sealing member at the periphery of the diaphragm and positioned between the diaphragm and the cylinder and one of its heads, and means firmly securing the outside and inside portions of the sealing member, but leaving the intermediate portion free to flex under relative expansion and contraction of the diaphragm and the cylinder.

2. A centrifugal pump comprising a cylinder, heads for each end thereof, a plurality of diaphragm elements assembled in the cylinder and an annular gasket of lexible material having.

its inner edge clamped between two of the diaphragm elements and its outer edge clamped between one end of the cylinder and one head to form a seal for the discharge end of the pump and to permit limited movement of the diaphragm elements with respect to the cylinder.

3. In a centrifugal pump of the type described, a cylinder, a pair of heads therefor, a plurality of diaphragm elements assembled therein, an annular gasket of flexible material to seal the discharge end of the pump, means to clamp the outer edge of the gasket between the cylinder and one of the heads, and means to clamp the inner edge between two of the diaphragm elements to permit relative movement between the cylinder and the diaphragm.

ANTHONY L. MCHUGH. 

